We present the current status of the analysis of about 1.7 billion K_S K_L pair events collected at DA{Phi}NE with the KLOE detector to determine the branching ratio of K_S -> {pi}e{ u} decay and the lepton charge asymmetry. This sample is ~4 times l
arger in statistics than the one used in the previous most precise result, from KLOE as well, allowing us to improve the accuracy on the measurement and related tests of CPT symmetry and Delta S = Delta Q rule.
We present the current status of the analysis of about 1.7 billion KSKL pair events collected at DAFNE with the KLOE detector to determine the branching ratio of KS -> pi e nu decay and the lepton charge asymmetry. This sample is ~4 times larger in s
tatistics than the one used in a previous KLOE analysis, allowing us to improve the accuracy of the measurement and of the related tests of CPT symmetry and Delta S = Delta Q rule.
The DAFNE collider, located in the Frascati National Laboratories of INFN, has two main rings, where electrons and positrons are stored to collide at a center of mass energy of 1.02 GeV, the phi resonance mass. KLOE-2 experiment is located at the col
lider interaction region. The detector is capable to observe and collect data coming from phi decay: charged and neutral kaon pairs, lighter unflavored mesons (eta, eta, f0, a0, omega/rho). In the first half of 2013 the KLOE detector has been upgraded inserting new detector layers in the inner part of the apparatus, around the interaction region in order to improve detector hermeticity and acceptance. The long shutdown has been used to undertake a general consolidation program aimed at improving the DAFNE performances. This contribution presents the phi-factory setup and the achieved performances in terms of beam currents, luminosity and related aspects together with the KLOE-2 physics program, upgrade status report and recent physics results.
We searched for evidence of a Higgsstrahlung process in a secluded sector, leading to a final state with a dark photon U and a dark Higgs boson h, with the KLOE detector at DAFNE. We investigated the case of h lighter than U, with U decaying into a m
uon pair and h producing a missing energy signature. We found no evidence of the process and set upper limits to its parameters in the range 2m_mu<m_U<1000 MeV, m_h<m_U.
Three new sub-detectors have been installed on May 2013 in the KLOE apparatus of Laboratori Nazionali di Frascati of INFN. Photon detection is improved by means of a small crystal calorimeter, named CCALT, in the very forward direction and of a tungs
ten-scintillating tile sampling device, named QCALT, instrumenting the low-beta quadrupoles of the accelerator. During the first DA$phi$NE operations, some preliminary runs, both with and without collisions, have been acquired allowing the commissioning of new subdetectors. In this paper, we report a brief description of QCALT and CCALT and a summary of the commissioning phase.
By studying the invariant-mass distribution of the $e^+e^-$ in conversion decays, it is possible to learn more about mesons structure and underlying quark dynamics. At KLOE, the study of the $phi to pi^0 e^+e^-$ process is currently going to be final
ized. At present, about 9000 events have been selected from a data sample of 1.7 fb$^{-1}$ from 2004/2005 data taking campaign. A very good agreement between data and Monte Carlo distributions has been achieved for all interesting kinematical variables. A preliminary invariant-mass spectrum of $e^{+}e^{-}$ is presented.
Neutral kaon pairs produced in phi decays in anti-symmetric entangled state can be exploited to search for violation of CPT symmetry and Lorentz invariance. We present an analysis of the CP-violating process phi->K_S K_L->pi+pi-pi+pi- based on 1.7 fb
-1 of data collected by the KLOE experiment at the Frascati phi-factory DAFNE. The data are used to perform a measurement of the CPT-violating parameters Delta_amu for neutral kaons in the contest of the Standard Model Extension framework. The parameters measured in the reference frame of the fixed stars are: Delta_ao = (-6.0 +- 7.7_{stat} +- 3.1_{syst}) x 10^{-18} GeV Delta_ax = ( 0.9 +- 1.5_{stat} +- 0.6_{syst}) x 10^{-18} GeV Delta_ay = (-2.0 +- 1.5_{stat} +- 0.5_{syst}) x 10^{-18} GeV Delta_az = ( 3.1 +- 1.7_{stat} +- 0.5_{syst}) x 10^{-18} GeV These are presently the most precise measurements in the quark sector of the Standard Model Extension.
Neutral kaons produced in the correlated pairs at the DAFNE phi-factory offer unique possibilities to perform fundamental tests of CPT invariance, as well as of the basic principles of quantum mechanics. The analysis of the data collected by the KLOE
experiment allows to improve results on several parameters describing CPT violation and decoherence and to measure the regeneration cross section on the beam pipe materials.
We have measured the ratio $sigma(e^+e^-rightarrowpi^+pi^-gamma)/sigma(e^+e^-rightarrow mu^+mu^-gamma)$, with the KLOE detector at DA$Phi$NE for a total integrated luminosity of $sim$ 240 pb$^{-1}$. From this ratio we obtain the cross section $sigma(
e^+e^-rightarrowpi^+pi^-)$. From the cross section we determine the pion form factor $|F_pi|^2$ and the two-pion contribution to the muon anomaly $a_mu$ for $0.592<M_{pipi}<0.975$ GeV, $Delta^{pipi} a_mu$= $({rm 385.1pm1.1_{stat}pm2.7_{sys+theo}})times10^{-10}$. This result confirms the current discrepancy between the Standard Model calculation and the experimental measurement of the muon anomaly.
We present a measurement of {eta} meson production in photon-photon interactions produced by electron-positron beams colliding with sqrt{s}=1 GeV. The measurement is done with the KLOE detector at the phi-factory DA{Phi}NE with an integrated luminosi
ty of 0.24 fb^{-1}. The e^+e^- --> e^+e^-{eta} cross section is measured without detecting the outgoing electron and positron, selecting the decays {eta}-->{pi}^+{pi}^-{pi}^0 and {eta}-->{pi}^0{pi}^0{pi}^0. The most relevant background is due to e^+e^- --> {eta}{gamma} when the monochromatic photon escapes detection. The cross section for this process is measured as {sigma}(e^+e^- -->{eta}{gamma}) = (856 pm 8_{stat} pm 16_{syst}) pb. The combined result for the e^+e^- -->e^+e^-{eta} cross section is {sigma}(e^+e^- -->e^+e^-{eta}) = (32.72 pm 1.27_{stat} pm 0.70_{syst}) pb. From this we derive the partial width {Gamma}({eta}-->{gamma}{gamma}) = (520 pm 20_{stat} pm 13_{syst}) eV. This is in agreement with the world average and is the most precise measurement to date.
